OpenGL

From Agar

OpenGL is the industry standard graphics interface, and the preferred rendering mode when using Agar on platforms where hardware acceleration is available.

Unlike SDL mode, which relies on the CPU for graphics operations, Agar running in OpenGL mode renders GUI elements as GL primitives, and manages graphic surfaces as texture elements. Typically, Agar applications running in accelerated OpenGL mode will be more responsive and use very little CPU when idle.

An Agar application can be forced to use OpenGL mode by passing the AG_VIDEO_OPENGL flag to AG_InitVideo().